Our invention relates generally to apparatus for the recording and/or reproduction of information with use of flexible magnetic disks, sometimes referred to as floppy disks, which are usually housed in protective envelopes or jackets. More specifically the invention pertains to such apparatus intended for use with double sided magnetic disks, that is, those having information bearing surfaces on both sides.
Flexible magnetic disks have found extensive acceptance in information processing and allied industries as compact data storage media. Being thin and limply flexible, the disks are commonly enclosed in more rigid, apertured envelopes to make up disk assemblies or cartridges that are self supporting.
It has recently been suggested to use both sides of the flexible magnetic disk for data storage, with a view primarily to higher capacity. Data storage devices for use with such double sided disks have also been proposed. Examples are Elliott et al. U.S. Pat. No. 3,879,757 and Tandon et al. U.S. Pat. No. 4,151,573. Another example is found in Noda U.S. patent application Ser. No. 434,400 filed Oct. 14, 1982.
Generally, in such double sided disk data storage systems, the generally opposed pair of transducer heads have their gapped surfaces machined to a mirrorlike finish for positive data transfer contact with the opposite faces of the disk. As the disk surfaces become smoother through use, the transducer heads make even closer contact therewith mechanically. Thus, during data transfer operation, the so called "stick slip" phenomenon takes place between transducer heads and magnetic disk. This phenomenon may give rise to the audible resonant vibration of the cantilevered carrier arm carrying one of the transducer heads, depending upon the material of which the carrier arm is made.
The other transducer head is usually gimbal mounted on a carriage which slides along guide rods and which is therefore free from audible resonant vibration. The carrier arm, however, is cantilevered on the carriage and sprung to bias the first mentioned transducer head into forced contact with the magnetic disk. The carrier arm is therefore far easier to vibrate by resonance. It is of course possible to reduce the audible vibration of the carrier arm by molding it from ABS (acrylonitrile-butadiene-styrene copolymer) resin or other comparatively pliant synthetic resins. However, the use of more rigid materials such as polyphenylene sulfide (PPS) is desirable to fabricate the carrier arm to very stringent dimensional tolerances and to improve other physical properties. In such cases the audible resonant vibration of the carrier arm has been almost unavoidable.